dedupe @Property rules

fixes #656

src/lib.rs

@@ -26105,6 +26105,24 @@ mod tests {
     "#,
       "@property --property-name{syntax:\"<color>+\";inherits:false;initial-value:#ff0 #00f}",
     );
+    minify_test(
+      r#"
+      @property --property-name {
+        syntax: '<color>';
+        inherits: false;
+        initial-value: yellow;
+      }
+      .foo {
+        color: var(--property-name)
+      }
+      @property --property-name {
+        syntax: '<color>';
+        inherits: true;
+        initial-value: blue;
+      }
+    "#,
+      "@property --property-name{syntax:\"<color>\";inherits:true;initial-value:#00f}.foo{color:var(--property-name)}",
+    );
   }
 
   #[test]

src/rules/mod.rs

@@ -498,6 +498,7 @@ impl<'i, T: Clone> CssRuleList<'i, T> {
   ) -> Result<(), MinifyError> {
     let mut keyframe_rules = HashMap::new();
     let mut layer_rules = HashMap::new();
+    let mut property_rules = HashMap::new();
     let mut style_rules =
       HashMap::with_capacity_and_hasher(self.0.len(), BuildHasherDefault::<PrecomputedHasher>::default());
     let mut rules = Vec::new();
@@ -810,6 +811,13 @@ impl<'i, T: Clone> CssRuleList<'i, T> {
           if context.unused_symbols.contains(property.name.0.as_ref()) {
             continue;
           }
+
+          if let Some(index) = property_rules.get_mut(&property.name) {
+            rules[*index] = rule;
+            continue;
+          } else {
+            property_rules.insert(property.name.clone(), rules.len());
+          }
         }
         _ => {}
       }